Liu is in a critical condition, and his blood pressure has dropped, according to a statement from the First Hospital of China Medical University in Shenyang, where Liu is being treated for terminal cancer under medical parole. In answer to recurring questions from reporters at the daily news conference Monday, Foreign Ministry spokesperson Geng Shuang repeated the often-heard lines that "related countries should respect the judicial sovereignty of China" and not "interfere in China's internal affairs".
An unnamed family member of Liu told a staff member at the information centre on Sunday evening that Liu Xiaoguang and his wife were under surveillance and unable to tell other family members about Liu's condition.
He was recently moved from jail to a hospital in the city of Shenyang to be treated for late-stage liver cancer.
A couple of video clips of Liu have appeared on YouTube, which is blocked in China, since his sickness came to light and on Sunday, two new ones were posted in which two foreign men, apparently the German and US doctors, appeared to praise the quality of care Liu has received.
Liu's plight has come under a global spotlight amid allegations from his supporters that he had become gravely ill because his cancer wasn't detected and treated in time in prison - and that China has refused to let him seek treatment overseas for political reasons despite calls from other governments, including the US.
Mr Liu, 61, was moved from prison - where he spent nearly eight years - to a hospital in the northeastern city of Shenyang recently after being diagnosed with liver cancer. In 2010, he won the Nobel Peace Prize for his work campaigning for human rights in China.
Nicholas Bequelin, Amnesty International's East Asia director, said Sunday that the doctors' recommendations showed that China was lying when it said that Liu was too sick to travel.
Hu said the Chinese government avoided bringing Liu to Beijing as it is preparing for a major party congress there in the autumn. When asked if filming was not allowed because of Liu Xiaobo, they said: "Who's that?"
Asked if Liu was being treated there, the man, whose ID badge identified him as Teng Zhi, said: "Regardless of whether he is here or not, you can not go in unless you are a family member".
They sat down holding placards with images of Liu and said they would not leave until he is released from China.
The Chinese government, which continues to censor domestic news coverage of Liu, has been waging a public relations offensive in the face of strong global reactions to the story.
A video clip surfaced on Monday of what appeared to be a foreign expert, Markus W. Buchler of Heidelberg University, addressing Liu's wife, Liu Xia, to tell her that Chinese doctors were doing their utmost to help Liu and were "very committed to his treatment".
"It seems that security organs are steering the process, not medical experts", the embassy said.